E. C. Meyers, G. M. McFarquhar, B. F. Jewett, S. W. Nesbitt University of Illinois at Urbana-Champaign 11 May 2010 Vertical Velocity and Microphysical Distributions Related to the Rapid Intensification of Hurricane Dennis (2005) E N W S Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth.”

E N W S Image Science and Analysis Laboratory, NASA-Johnson Space Center. "The Gateway to Astronaut Photography of Earth.”

Guiding Questions How do such isolated, inner-core, most- intense vertical velocities (i.e., convective bursts) cause and/or respond to rapid intensification (RI) of tropical cyclones?

Guiding Questions How do such isolated, inner-core, most- intense vertical velocities (i.e., convective bursts) cause and/or respond to rapid intensification (RI) of tropical cyclones? What statistics can be gathered from a high- resolution simulation regarding convective bursts’ distributions, magnitudes, vertical structures, durations, proximities to the vortex center, and trends as precursors to RI?

Limited understanding of how RI may relate to convective bursts – 3-D structure – Timing – Distributions of latent heat Motivation

Limited understanding of how RI may relate to convective bursts – 3-D structure – Timing – Distributions of latent heat Need to statistically characterize the morphology of these isolated, intense vertical velocities and associated microphysics within observational voids Motivation

WRF Configuration Horizontal… 27-km 9-km 3-km 1-km d01 d02 d03 d

WRF Configuration Vertical…

Dennis Track 00Z 06 July Z 07 July Z 08 July 2005

*10 min * Intensity

*10 min * Intensity -19 hPa (6 h) -1

*10 min * Intensity

* * *10 min +36 kts (6 h) -1

14:20Z-14:32Z 09 July 2005 [dBZ] [m s -1 ] 14:45Z-15:03Z 09 July 2005 Guimond et al. (2010, JAS) Are column- confined, averaged, and low-to-mid- level interpretations valid? Convective Bursts?

10-min 2-min

10-min 2-min

CFAD 9 hours before RI 9 hours during RI Column Max Reflectivity s

9 hours before RI 9 hours during RI during – before RI CFAD Difference

hourly 99.9 th percentile w [m s -1 ]

Interpretation of RI depends on: – Interval examined – ∆p min or ∆|v 10-m, max | perspective Discrete vertical level statistics provide better identification of convective bursts than column averages or thresholds Outlier (e.g., 99.9 th percentile) w better indicators of RI than averages – Precursor to RI at upper levels (e.g., 14 km) – Continual broadening and convergence toward TC center CONCLUSIONS

CONCLUSIONS, CONT’D Outlier (e.g., 99.9 th percentile) w at lower levels (e.g., 6 km), however, increase only after onset of and during RI Manifested as an increase in latent heating Precursor w have unnoticeable impact on latent heating – Vertical structure – Thresholds for definition Implications of these upper-level, rapidly accelerating updrafts for RI?

Acknowledgements AMS Graduate Fellowship, Earth Science Div. of the Science Mission Directorate NASA Headquarters under the NESSF Program NASA Hurricane Science Program – Grant NNX09AB82G NOAA/GFDL WRF Modeling Community TeraGrid Seemingly endless list of students, staff, and faculty at the University of Illinois at Urbana-Champaign and beyond THANK YOU! Boston.com “Hurricanes, as seen from orbit”

*LH, Abe

< -80

Precursor to RI? Colin et al. (2009, Nature Geosci.)

*history interval accumulation ≤ 5 > 3 > 15

≤ 0 > -2 < -10 output

≤ 0 > -60 < -540

> 1.0 < 5.0 > 30.0 < 40.0

2030Z7th

2036Z7th

2042Z7th

2048Z7th

2054Z7th

2100Z7th

Observed onset of RI

Every 6 hours from contour analysis of simulation

onset of simulated 24-hour period during which ∆p min ≤ -42 hPa Every 3 hours from contour analysis of simulation

onset of simulated 24-hour period during which ∆|v 10-m, max contour | ≥ +30 knots Every 6 hours from contour analysis of simulation

onset of simulated 24-hour period during which ∆|v 10-m, max contour | ≥ +30 knots Every 3 hours from contour analysis of simulation

hourly 99.9 th percentile w [m s -1 ]

Zhu and Zhang (2006, JAS) Li and Pu (2008, MWR) Relation to Microphysics only warm rain processes; hmmm… LI AND PU MARCH 2008 WSM3 WSM5 WSM6 Increasing inclusion of mixed-phase proc. graupel support Wang (2002)

Rogers (2010, JAS)

MEAN, convective regions

72.9°W 71.6°W 15.6°N 16.7°N (|V 10-m | ≥ 30 knots) contoured (interval = 5 knots) in black 18:00Z 06 July 2005

What About the Vertical?

> 35 < 40 > 15 < 20

< 364 > 372 < 374

> 370 < 374 > 358 < 362